The present invention generally relates to plasma guns, particularly to ablative plasma guns, and also relates to triggers for electric arc devices.
Electric arc devices are used in a variety of applications, including series capacitor protection as described in U.S. Pat. No. 4,259,704 of the present assignee, high power switches, acoustic generators, shock wave generators, and pulsed plasma thrusters. Such devices have two or more electrodes separated by a gap of air or another gas. A bias voltage is applied to the electrodes across the gap. A triggering device in the gap ionizes a portion of the gas in the gap, providing a conductive path that initiates arcing between the electrodes.
Conventional spark gap triggering involves application of high voltage pulses to a trigger pin. The trigger pulse magnitude depends largely on the bias voltage across the spark gap. Although such pulse triggering is widely used, the cost of the trigger source and its electronics is several times higher than the cost of the main spark gap itself. For example, in a 600V system the required trigger voltage is at least 250 KV for a gap of 20 mm.